22 ' THE VOYAGE OF H.M.S. CHALLENGER. 



This differs from Cadulus curtus, Wats., in being one-third larger; the mouth is perhaps less 

 oblique, but being in both specimens much chipped, this may be accidental. The most remarkable 

 feature of difference is that it is perfectly round, and not, like the other, laterally compressed. I 

 attribute this difference to age. At all events, in the absence of a larger series of specimens, I 

 believe it safer to include both under one species. 



8. Cadulus obesus, Watson (PI. III. fig. 8). 



Cadulus obesus, Watson, Prelim. Report, pt. 2, Journ. Linn. Soc. Lond., vol. xiv. p. 527. 



Station 24. March 25, 1873. Lat. 18° 38' 30" N., long. 65° 5' 30" W. Culebra 

 Island, West Indies. 390 fathoms. Pteropod ooze. 



Shell. — Short, very broad, narrowed at both ends, little bent, and that almost entirely 

 toward the mouth, very much swollen in the middle, and bulging a good deal on the 

 concave curve, a little more attenuated behind, and very slightly laterally compressed 

 (in the proportion of 14 to a little less than 15). It is pretty strong, polished, translucent 

 white, with one, sometimes two opaque rings near the apex. Sculpture : A few very 

 vague and faint, distant, transverse lines. Mouth rather large, straight ; edge thin and much 

 chipped. Apical opening small, straight, chipped, narrowed inside by a minute shelf-like 

 projecting ring. L. 0"109 in. B. at mouth 0'02 ; greatest 0'04 ; at apex 0"01. 



This is nearly of the same proportions as Cadulus curtus, except being very much broader ; like 

 that, too, it is narrowed laterally. I have hesitated very much in making it more than a variety ; 

 but, on the whole, think it safer to reckon it as distinct. One specimen has its breadth exag- 

 gerated by a gibbous pad of enamel. 



9. Cadulus tumidosus, Jeffreys (PL III. fig. 9). 



Cadulus tumidosus, Jeffreys, "Valorous" Moll., Ann. and Mag. Nat. Hist., 1877, ser. 4, vol. xix. 

 p. 156. 

 „ . „ Jeffreys, "Lightning" and "Porcupine" Moll., Proc. Zool. Soc. Lond., 1882, 



p. 665, sp. 7, pi. xlix. fig. 8. 



Station 78. July 10, 1873. Lat. 37° 26' N., long. 25° 13' W. Azores. 1000 fathoms. 

 Volcanic mud. 



Station 85. July, 19, 1873. Lat. 28° 42' N., long. 18° 6' W. Canaries. 1125 fathoms. 

 Volcanic mud. 



Habitat. — N. Atlantic, "Valorous," Station 12, 1450 fathoms. In the "Porcupine" 

 Channel slope, 557 fathoms ; Bay of Biscay, 292-1095 fathoms. "Josephine" expedi- 

 tion, 110-550 fathoms. 



Fossil. — At Messina from the Pliocene (Jeffr.) 



